A pioneering technology helped to make Sunnyside a neighborhood: the first electrically powered streetcar in San Francisco began running from downtown out to the new neighborhood in 1892, making it possible for people to live here.
Capitalist Behrend Joost hired a sharp engineer from the Midwest named John Wesley Hartzell, who designed the system. Unfortunately, Joost was a incompetent business manager, a scrappy underdog constantly being sued by everyone from his creditors to his employees to the people injured by his poorly run streetcars. Joost lost the railway, but it eventually became part of SF’s municipally run public transport system by the early 1900s.
Here is a great collection of photos from SFMTA: http://sfmta.photoshelter.com/gallery/Sunnyside-Powerhouse/G0000bK1E7CPP58c/C0000gA7yYOiLzG0